The use of a hand operated pointing device for use with a computer and its display has become almost universal. By far the most popular of the various devices is the conventional (mechanical) mouse, used in conjunction with a cooperating mouse pad. Centrally located within the bottom surface of the mouse is a hole through which a portion of the underside of a rubber-surfaced steel ball extends. The mouse pad is typically a closed cell foam rubber pad covered with a suitable fabric. Low friction pads on the bottom surface of the mouse slide easily over the fabric, but the rubber ball does not skid. Rather, the rubber ball rolls over the fabric as the mouse is moved. Interior to the mouse are rollers, or wheels, that contact the ball at its equator and convert its rotation into electrical signals representing orthogonal components of mouse motion. These electrical signals are coupled to a computer, where software responds to the signals to change by a ΔX and a ΔY the displayed position of a pointer (cursor) in accordance with movement of the mouse. The user moves the mouse as necessary to get the displayed pointer to a desired location or position. Once the pointer on the screen points at an object or location of interest, a button on the mouse is activated with the fingers of the hand holding the mouse. The activation serves as an instruction to take some action, the nature of which is defined by software in the computer.
In addition to mechanical types of pointing devices like a conventional mouse, optical pointing devices have also been developed, such as those described in the incorporated patents and patent application. In one form of an optical pointing device, rather than using a moving mechanical element like a ball in a conventional mouse, relative movement between an imaging surface, such as a finger or a desktop, and photo detectors within the optical pointing device, is optically sensed and converted into movement information.
Prior optical pointing devices have used an optical navigation sensor chip in conjunction with a micro controller. Agilent, Inc., the assignee of the present application, produces optical navigation sensor chips that are suitable for use in optical pointing devices, such as an optical mouse. Typically, the micro controller is under the design control of the mouse manufacturer. Optical navigation sensor chips optically sense movement (e.g., of an optical mouse relative to a work surface or imaging surface), and calculate and report motion information. The micro controller is typically responsible for the overall management of the mouse, including receiving motion information from the optical navigation sensor chip and reporting the motion information to the host computer (or other host device), handling all other communications with the host computer, handling universal serial bus (USB) interrupts, deciding when to turn components on/off, handling the buttons and Z wheel of the mouse, as well as other operational and regulatory functions.
It would be desirable to provide an optical screen pointing device that utilizes a single chip for gathering, processing, and outputting motion data in a serial format for direct use by a host computer or other host device.